fix(compiler): exclude outDir from compiler source files (#2375)

Closes #2350
Closes #2374

Author: ahnpnl

src/compiler/ts-compiler.ts

@@ -18,7 +18,7 @@ import type {
   CustomTransformers,
 } from 'typescript'
 
-import type { ConfigSet } from '../config/config-set'
+import { ConfigSet, TS_JEST_OUT_DIR } from '../config/config-set'
 import { LINE_FEED } from '../constants'
 import type { ResolvedModulesMap, StringMap, TsCompilerInstance, TsJestAstTransformer, TTypeScript } from '../types'
 import { rootLogger } from '../utils/logger'
@@ -75,7 +75,12 @@ export class TsCompiler implements TsCompilerInstance {
     }
     // Initialize memory cache for typescript compiler
     this._parsedTsConfig.fileNames
-      .filter((fileName) => !this.configSet.isTestFile(fileName))
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      .filter(
+        (fileName) =>
+          !this.configSet.isTestFile(fileName) &&
+          !fileName.includes(this._parsedTsConfig.options.outDir ?? TS_JEST_OUT_DIR),
+      )
       .forEach((fileName) => this._compilerCacheFS.set(fileName, 0))
     this._cachedReadFile = this._logger.wrap(serviceHostTraceCtx, 'readFile', memoize(this._ts.sys.readFile))
     /* istanbul ignore next */

src/config/config-set.spec.ts

@@ -13,7 +13,7 @@ import { getPackageVersion } from '../utils/get-package-version'
 import { normalizeSlashes } from '../utils/normalize-slashes'
 import { mocked } from '../utils/testing'
 
-import { ConfigSet, MY_DIGEST, TS_JEST_OUT_DIR } from './config-set'
+import { ConfigSet, MY_DIGEST } from './config-set'
 
 jest.mock('../utils/backports')
 jest.mock('../index')
@@ -53,7 +53,6 @@ describe('parsedTsConfig', () => {
   it('should override some options', () => {
     expect(get({ tsconfig: { inlineSources: false, outDir: 'build' } }).options).toMatchObject({
       inlineSources: true,
-      outDir: TS_JEST_OUT_DIR,
     })
   })
 

src/config/config-set.ts

@@ -158,8 +158,6 @@ export class ConfigSet {
     // to clear out else it's buggy
     out: undefined,
     outFile: undefined,
-    // ensure that `LanguageService` won't pick up things from `build` folder which can lead to emit skipped error
-    outDir: TS_JEST_OUT_DIR,
     composite: undefined, // see https://github.com/TypeStrong/ts-node/pull/657/files
     declarationDir: undefined,
     declarationMap: undefined,
@@ -421,6 +419,10 @@ export class ConfigSet {
         finalOptions.allowSyntheticDefaultImports = true
       }
     }
+    // Make sure when allowJs is enabled, outDir is required to have when using allowJs: true
+    if (finalOptions.allowJs && !finalOptions.outDir) {
+      finalOptions.outDir = TS_JEST_OUT_DIR
+    }
 
     // ensure undefined are removed and other values are overridden
     for (const key of Object.keys(forcedOptions)) {